The invention relates to a support prop for underground mining use in longwall and gallery with telescopic external and internal prop, and connected with the latter a crown head, collar ring and sole plate, as well as a pressure limiting valve integrated into the prop head and a filling and drawing valve positioned on the internal prop.
In underground mining and in tunnel construction support props, also called individual props, are used to secure cavities which were created by mining. Known support props are constructed as single or multiple telescope props and are preferably operated with a water-in-oil emulsion. This emulsion is pumped via pumps located outside the longwall or at some distance from the respective operating site by way of suitable hose lines to the respective support prop. The inside of the support prop is then connected by way of so-called setting guns with the pump and is accordingly filled and extended, and in this way is clamped between the topwall and footwall. In the known support props the external and internal props with their different diameters are welded both to the crown head and to the collar ring and the sole plate. Because mostly improved pipes are used today, i.e. strain-hardened pipes, the structure is negatively affected or even destroyed when the crown head, collar ring and sole plate are welded on, whereby an exact testing of these modified properties is not possible. In addition, the filling and drawing valve used becomes relatively complicated, whereby this filling and drawing valve as a rule is attached to the internal prop from the outside and is coupled with the pressure limiting valve, in order to enable the coupling of the individual functions setting, drawing and protecting against overload in this manner with the integrated valve. These valves, particularly the pressure limiting valve, exhibit a relatively small flow volume, resulting thus in a too low insertion speed in cases of actual overloads. For this reason, high volume pressure limiting valves integrated in the prop head (DE-OS 40 35 874.7) have been created, in which relatively high volumes of up to 1,000 l per minute can be achieved. But the disadvantage here is that they still require the relatively complicated setting and drawing valve which is attached to the outside of the internal prop.